Both [1]}, [2]} and [3]}, [4]} concentrate on the role of labor (and later division of labor and social/family organization) and innovations which increase area productivity (like storage or tools, requiring relatively more labor for harvesting, building, and tool processing). Both authors neglect the role of labor-independent innovation, or innovations which increase both area and labor productivity; these are innovations in the resources themselves, such as cultivation of higher-yielding grains or imported high yield varieties, or their management such as water rights; this distinction may not be unambiguous for all innovations, it is used here conceptually. Labor-independent innovation can be stimulated by diversity and density of a population, both of which are positively related to population size. Already [5]} wrote “The more diversified [..], by so much will they be better enabled to seize on many and widely diversified places in the polity of nature”. Translated into the realm of innovativity, Darwin's “seizing of places”, or niche occupation, would be the realization of technical and scientific opportunities. As for density as a stimulus of innovation, it is aggregation which constitutes a motor of technological and cultural change [6]}, [7]}This does not, however, give the reason for a particular choice of one innovation over another [8]}..
